The invention concerns an arrangement including an internal combustion engine ignition device having a spark plug and a spark plug mounting in which the spark plug can be fastened in a fastening region, and a cylinder head in which the spark plug is or can be mounted by way of the spark plug mounting. The cylinder head has a cylinder head cooling cavity, and the spark plug mounting has a temperature control medium chamber which is separate from the cylinder head cooling cavity and has a medium feed conduit and a medium discharge conduit. The invention further concerns an internal combustion engine ignition device including a spark plug, a spark plug mounting which receives the spark plug and which can be fitted in a cylinder head of an internal combustion engine, as well as an internal combustion engine, in particular a gas engine, having the arrangement and internal combustion engine ignition device.
In the case of internal combustion engines, particularly stationary gas engines, there are basically two possible ways of fitting or screwing spark plugs in a cylinder head.
The first option is that of screwing the spark plug directly into a screwthreaded bore on the cylinder head end. The screw-in screwthread is in that case provided directly in the casting material of the cylinder head.
The second possibility involves providing a separate spark plug mounting (spark plug sleeve) which in turn is screwed or clamped in the cylinder head. Particularly in the case of gas engines with prechamber ignition—that is to say where mixture ignition is effected by means of ignition sparks in a prechamber and from there a mixture is ignited in the main combustion chamber by way of the ignition jets issuing from the transfer bores—it is necessary to use separate spark plug mountings for structural reasons.
Intensive development activities in the field of gas engines in recent years have meant that it has been possible to greatly increase the specific power levels (for example power per piston displacement) of the gas engines. The result of this however is that the spark plugs are subjected to a high thermal loading. Therefore the methods of cooling used hitherto are in part no longer sufficient.
To avoid severe heating of the spark plugs in the high-load mode of the engine, the spark plug mountings are generally water-cooled for that reason. Particularly with high thermal loadings it is already known to provide cooling bores in the spark plug mounting in order to pass the cooling medium in the cylinder head closer to the spark plug screwthread and there achieve a better cooling action. A disadvantage in that respect is inter alia that temperature control of the spark plug is always dependent on the temperature of the cooling medium in the cylinder head cooling cavity and the bores only extend in point configuration in the direction of the spark plug. As a result, this does not involve uniform temperature control of the spark plug.
In that respect, JP 7-14596 discloses a spark plug mounting, by way of which a spark plug is fitted in a cylinder head. In that case, a cooling chamber is provided in the cylinder head and a water passage is provided in the spark plug mounting. Those two water passages or chambers are supplied from a single common water supply and are connected together. The disadvantage with that configuration is that the temperatures of the cooling passages always influence each other. In other words, if for example, the water in the region of the spark plug mounting is very greatly heated, then during the further cooling operation that also has a strong inevitable direct influence on the temperature of the cooling medium in the cylinder head.